Quote from the Japan TimesQuestion
Perhaps you have not paid much attention to men's restrooms in Japan, but in the vast majority of public toilets the urinals and the men using them are completely visible to anyone passing by. Do you think this is done on purpose? Or is it just the result of bad design? Japanese are generally very discreet, so it's hard to understand why the heck they are so public about this one thing.

AnswerBelieve me, this is something that's hard not to notice. I too have wondered about the open nature of answering the call of nature, so I was more than happy to take your question over to the Japan Toilet Association. Chairman Koo Ue gave me a gracious reception but confessed he couldn't quite understand why we were asking.

"Is this so surprising for foreigners?" he queried. "Can't you see into men's restrooms in other countries?"

Quote from the Wikipedia
During the Jomon period, settlements were built in a horseshoe shape, with a central plaza in the middle and garbage heaps around the settlement. In these garbage heaps, calcified fecal remains of humans or dogs, so called coprolites, were found,[8] indicating that these garbage dumps were also used as toilets.

The earliest sewer systems are from the Yayoi period (300 BC to A.D. 250).[9][10] These systems were used in larger settlements, probably in combination with toilets. A possible ritual site, that may also have been a toilet using flowing water, dating back to the early 3rd century was found in Sakurai, Nara.[8]

Another cesspit analyzed by archaeologists in detail was found at the site of the Fujiwara Palace in Kashihara, Nara, the first location of the imperial city from 694 to 710.[8] This toilet was constructed over an open pit similar to an outhouse. During the Nara period (710 to 784), a drainage system was created in the capital in Nara, consisting of 10-15 cm wide streams where the user could squat over with one foot on each side of the stream.

Wooden sticks called chu-gi were used as a sort of toilet paper.[8][11] In earlier days seaweed was used for cleaning,[12] but by the Edo period, these had been replaced by toilet paper made of washi (traditional Japanese paper).[13][14] In the mountainous regions, wooden scrapers[11] and large leaves were used too.

Often, toilets were constructed over a running stream; one of the first known flushing toilets was found at Akita castle, dating back to the 8th century, with the toilet constructed over a diverted stream.[8] However, historically, pit toilets were more common, as they were easier to build and allowed the reuse of the feces as fertilizer[15]—very important in a country where Buddhism and its associated vegetarianism acted to reduce dependence on livestock for food, though seafood has always been an important part of the Japanese diet.

In fact, the waste products of rich people were sold at higher prices because their diet was better.[12] Various historic documents dating from the 9th century describe laws regarding the construction of fresh and waste water channels, and detail the disposal procedures for toilet waste.[8]

In Goa, India, we used the "Pig Toilet".
Charly, the white toilet pig, would wait outside when somebody headed toward the open shed in the back of the garden. You enter the throne room with two steps and while you squat up there, Charly comes grunting from below and waits for his breakfast.
This kind of toilet never smells bad, Charly is very efficient.

And the white pigs are never eaten in Goa, only the black pigs end up roasted.
Gabi Greve

Japanese God of the Toilet kawaya no kami 厠の神厠神 Benjogami
Kookagami 後架神 Kokagami

source : apgdj がんばり入道ほととぎす ganbari nyuudoo hototogisu
Ganbari Nyūdō 加牟波理入道 is a Yokai monster "God of the toilet".
He is said to disappear if you chant the above proverb, but show up if you do that on the last day of the year.
If you chant this proverb on the last day of the year, it will bring bad luck.
- More about this Yokai monster: . Ganbari Nyūdō 加牟波理入道 Ganbari Nyudo .

- - - - - Tr. and comment by Chris Drake :even the god
of the outhouse is back --
plum blossoms

This is a somewhat mysterious hokku. It is from the end of the 10th month (November), and the next two hokku in Issa's diary are about greeting gods returning home from the Izumo Shrine in western Honshu, where all the gods in the land have gathered for their annual divine conference during the 10th month according to Shinto tradition. The 10th month is also called the "Godless Month," since the gods of Japan are "not" in the normal areas where they "are" for the other eleven months because they have gone to Izumo. The second line of Issa's hokku seems to imply that at the end of the 10th month -- right now -- the gods have all returned, and even the outhouse god "is here" once more.

Plum blossoms are normally a 1st-month (February) spring image. When Issa writes a hokku about a season different from the one he's in, he is usually careful to write the season of the hokku up above the hokku, but there is no special seasonal indication above this hokku, so it's probably a winter hokku. Perhaps the plum tree near the outhouse has bloomed early, something plums are known to do occasionally. My guess is that the plum tree is blooming early and that Issa takes this as a sign that even the outhouse god, who had been away, has now returned from Izumo after the big conference of the gods there. The outhouse god "is" in the small structure once more. Perhaps Issa can see the plum blossoms through the outhouse window.

The privy or outhouse god (kawaya-gami) was one of the most important household gods, along with the hearth/fire and well/water gods, and newborn children were taken to "greet" the outhouse god on the third day after birth. Depending on the location, the god was believed to be either female or a male-female pair, so Issa's hokku may be about a pair of gods, not one god, although there's no indication of singular or plural here. What seems to surprise Issa isn't that the outhouse is the habitation of a god -- something that's very common in folk belief. What he seems to find interesting is that the plum tree near the privy is blooming already and that this seems to indicate that the god/gods is/are back in the outhouse along with him. The hokku seems to be about companionship --and humorous in tone.

The same god was also the god of the village birth hut or huts (ubuya), where women gave birth and which only women could enter. The traditional word for outhouse was kawaya or "river hut," since it was usually built near or by a stream or river, but Issa uses setchin, a word that came to Japan along with Buddhism. It apparently was the name of a Chinese monk, but its characters (雪隠) literally mean "snow, hidden," making it an elegant euphemism. The word is no longer as widely used as it was in Issa's time.

In some regions of Japan, Fudo is venerated as the Deity of the Toilet Benjo no Fudo Son 便所の不動尊
Benjogami no O-Fudo-Sama 便所神のオフドウサマ

- - - - - - - - - -Akita 秋田県 - Yokote 横手
During the New Year rituals people pay their respect to Fudo at the Toilet. They clean the place with special care and make offerings.
This is O-Fudo Mairi 不動参り, often on the 15th day of the first lunar month.
The head of the family paints pairs of eyes, one for each member of the family, and hangs the paper in the toilet. This is an amulet to protect the family from eye diseases.
In other regions a 不動の絵馬 votive tablet with Fudo is hung in the toilet.
Here we have three keywords: 眼・年中行事・不動明王というキーワード.

- - - - - - - - - -Iwate 岩手県 - 東和町 Towa
Once an old woman was cleaning the toilet, but happened to get some dirt on the Fudo venerated in the toilet 便所の不動尊. Then came the village sports event in autumn, but this time she could not participate because her whole body ached for two days.
Now she knew what to do. She cleaned the statue of Fudo with some wand and yes - her pain was gone.

- - - - - - - - - -Okayama 阿哲郡 Atetsu gun 哲西町 Tessei cho
真庭郡 Maniwa gun 落合町 Ochiai cho and Kuse cho 久世町
In the hamlet of Tessei they call the god of the toilet 不動様 "Fudo Sama".
When someone has to use the outhouse in the evening they call on the Deity of the Outhouse.
「便所の神さん、便所の神さん、明日の晩からは必ずの用があって、よう参りませんけえ」

akaname, aka name 垢嘗（あかなめ） "licking Aka dirt"
in the toilet and the bathroom

歌川芳員『百種怪談妖物雙六』より「底闇谷の垢嘗」

Akaname means filth licker in Japanese; aka is an homonym for red and filth, so the akaname is often described as being red in colour.
The akaname is the "personification of the fear of using a dark bathroom late at night". It is said to come out at night to lick up the grime and dirt that accumulates in unclean bathrooms.- - - More in the WIKIPEDIA !

This was a good business, getting some money first and then sell the manure.

It all started on Benten Island in the lake of Ueno there was no public toilet, but during the first visit of the New Year, the island was crowded with visitors. This was the high time for the portable toilet for rent business.
The idea caught on and soon more such "business" was done in all parts of Edo.

In Edo there were various free public places for "small business".
And in many places were signboards "No pissing here" 小便無用.
Later local farmers put up public toilets to use for a small fee and thus collected the manure for their fields.

雪隠に貸し参らせて土に膝
setchin ni kashi-mairasete tsuchi ni hiza

going to rent
a portable toilet
with knees in the dirt

When a person of higher rank used the toilet, the owner had to kneel down and wait till the business was done.

quote
There are two types of toilets in Japan: "Japanese style" and "Western style".

Public washrooms are often equipped with both toilet styles, although some older facilities might have only Japanese style toilets, while some newer facilities might have only Western style toilets. The toilets in most public homes and hotels are Western style.

Western style toilets in Japan often feature options such as a heated ring, a built-in shower and dryer for your behind and an automatic lid opener. Both Western and Japanese style toilets usually have two flush modes: "small" (小) and "large" (大), differing in the amount of water used.

Although the situation has improved considerably in recent decades, toilet paper is not always provided in public washrooms. Therefore, it is recommended to carry a small package of tissues. Similarly, because paper towels or dryers are not always provided, it is recommended to carry a handkerchief.

When using the washroom in a private home, minshuku or ryokan, you will often find toilet slippers for exclusive use inside the washroom. Leave your usual slippers outside the washroom, and do not forget to change back into them, afterwards, to avoid an often committed cultural faux pas.
MOREsource : www.japan-guide.com

French translator Jean Cholley interprets no setchin ("field outhouse") as a person doing his business in an open field; En village de miséreux: Choix de poèmes de Kobayashi Issa (Paris: Gallimard, 1996) 167.
My Japanese advisor, Shinji Ogawa, concurs. I had assumed that no setchin is an outhouse in a field, but Shinji notes that an outhouse is called setchin, not no setchin. Shinji adds, "Though in an open field, in most cases people use a hidden place.

In this case, the footprints in the snow reveal the hideout. Issa humorously uses the word hairu ("enter") to regard the open field as an outhouse." In other haiku where Issa uses the expression no setchin, I've translated with the phrase, "pooping in the field," but here, since his joke depends on the word "outhouse," I've kept this word. The reader needs to keep in mind that this "outhouse" is imaginary.

My Japanese advisor, Shinji Ogawa, concurs. I had assumed that no setchin is an outhouse in a field, but Shinji notes that an outhouse is called setchin, not no setchin. The phrase, kado no matsu ("gate's pine") refers to a traditional New Year's decoration made of pine and bamboo. Shinji believes that Issa's use of it in this context is humorous. Instead of a decoration, Issa means an actual pine tree. Shinji writes, "I think that someone is doing his business behind a pine tree, so that the tree is at the moment occupied." The "outhouse" is imaginary.

On the way to the outhouse--
the white of the moonflower
by torchlight.tr. Hass

moonflowers white
at night by the outhouse,
torch in handtr. Daivd Barnhill

moonflowers so white
at night, alongside the outhouse
in the light of a torch

Makoto Ueda says of this haiku:"Alludes to a scene in the chapter 'Yuugao' (Moonflower) in 'Genji monogatari', where Prince Genji reads Lady Moonflower's poem by torchlight.
'Kooka 後架', literally 'hindhouse', is a Zen term for an outhouse, which was usually located behind the monastery. The poet ... was surprized to find moonflowers blooming on the roof."

Basho age 38, 延宝9年
The meter here is 5 3 3 4 3 3 .

a white evening face flower
taking to the privy at night
a candle Tr. Reichhold

Like the aroma of fresh-baked bread or the sweet fragrance of a flower shop, the stench of a toilet can be just as memorable, albeit not in as nice a way.

Despite Japan’s reputation for high-tech toilets and Washlets that do everything except brush your teeth (thank God), a surprising number of households in Japan still have the old-style “pit toilets.” These toilets have a porcelain bowl, but no running water to flush in or out. You just squat over the hole and drop your goods into a cement pit waiting at the bottom. It’s basically an in-house outhouse.

Almost all the houses are this style on the islands in the Seto Inland Sea as well as many dwellings in Japan’s countryside. Our toilet reporter takes an in-depth look at how these pit toilet systems work. We bet you’re just dying to know!

The most surprising thing about these bathrooms, perhaps, is that they don’t smell foul. This is because each house has a fan connected to the toilet pit that works continuously to propel the stench outside rather than letting it creep back into the building.

Oni no manaita 鬼の俎 / 鬼のまな板 "Devil's cutting board""Devil's Chopping Board"It had been said that a devil ate people after chopping them on this stone board..https://kappapedia.blogspot.jp/2017/04/oni-landscapes.html.

Before entering the outhouse, you have to cough lightly to clear the throught and give the Toilet Deity a signal of your coming.

Once 比丘 a nun forget to do this, went inside and so dirt got on the demon mask. The Demon got angry and prevented the nun to come again, causing hermental disturbances. .https://kappapedia.blogspot.jp/2017/09/oni-men-mask-legends.html.

When most of the Kami left for Izumo, only Ebisu and the Benjo no Kami of the Toilet stayed back in the homes. They were the rusui no kami, Gods keeping back home. For them, the round rice dumplings were an offering. Also calledinokori dango 居残りダンゴ round rice dumplings for those left behind.

. kannazuki, kaminazuki 神無月 かんなづき "Gods are absent" month .The tenth lunar month (now November), after the harvest when the Japanese gods had done their duty, they left their local shrines for a bit of a vacation and went to the Izumo Shrine..https://japanshrinestemples.blogspot.jp/2017/10/tanokami-inoko-legends.html.